For over a century dentists treated tooth decay by removing both diseased portions of the tooth and healthy structure deemed at risk for future decay. In the 1970s, though, a new approach emerged, known as Minimally Invasive Dentistry (MID). This practice protocol attempts to preserve as much of the healthy structure as possible.

Before MID, dentists followed a decay treatment protocol developed in the 19th Century. A part of this became known as extension for prevention calling for dentists to remove healthy structure considered vulnerable to decay. Besides reducing the tooth's volume, this practice also resulted in, by today's standards, larger than necessary fillings.

It was thought that removing this additional material would make it easier to clean bacterial plaque, the source of decay, but later, research showed the practice couldn't guarantee the teeth wouldn't be reinfected.

Since then we've learned a lot more about teeth and have developed new ways to detect decay at earlier stages. X-ray imaging, for example, has transitioned largely from film to digital technology, providing more detailed images at greater magnification. This, along with laser fluorescence and infrared cameras, has made it easier to detect the first tiny stages of decay.

We can also limit tooth decay damage by boosting enamel strength with fluoride applications and sealants or reducing decay-causing bacteria with anti-bacterial rinses. We've also seen advancement in techniques like air abrasion that remove decayed tooth material while leaving more healthy structure intact better than using a traditional dental drill.

Restoring teeth after treatment has also improved. While dental metal amalgam is still used for some fillings, the main choice is now composite resin. These new tooth-colored dental materials require less tooth preparation (and thus less material loss) and bond well to the remaining structure, resulting in a stronger tooth.

Following a MID protocol leads to less intervention and less time in the dentist's chair. It also means preserving more of a natural tooth, an important aim in promoting long-lasting dental health.